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2`Sheets--Sheet l.

a. R. GREGG. Pneumatic Railways.

Patented June 29,1875.

' ,2Sheets-Sheet2. B. R. GREGG.

Pneumatic Railways.

No. 165,092, Patentedjune29,ll8?5.

wnNEssEs. mvENToR.

THE GRAPHIC C0.PHOT0 LITH.39 5:4 PARK PLAOEJLY.

Unrrnn Srarns PATENT cierren,

nothin acnneaor BUFFALO, `niivvronicr iMPnovEMENr iu Pneumatic nAiLwAvs.

Specification forming part of Letterslatent No. 165,092, dated .l une 29, 1875; application filed March 16, 1874.

To all whom it may concern:

Be it known that I, BOLLIN R. GREGG, of the city of Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in the Gonstruction of Pneumatic Railways and Gars, of which the following 'is a full and exact de` scription:

My invention consists, first, in a pneumatic railway-tube, formed in cross-section, with a horizontal base, and sides and top circularV or arched; second, in the mode of constructing the same; third, in the mode of constructin g draft-cars to be operated in such tubes by atmospheric pressure. i

In the drawings, Figure 1 is a Vtransverse sectional view of the tube, with a dratt-car shown within it, Fig. 2, a side elevation of thepropelling-car; Fig.v 3, a side elevation of the pneumatic tube. 4, is an end view of the same at a station, with the doors open.

The method of constructingjmy pneumatic tube is as follows: On apreparedroad-bed of gravel or other suitable material, I lay ordinary wooden ties A A at suitable distances apart,.iand to these spike the rails B B of the track in the ordinary manner, placing them at the required width of gage. Outside of the rails, parallel with them, and as close as will allow the free passage of the car-wheels, Ilay a succession of square timbers, C C, of considerable size, in continuous line, the whole length of the track, and firmly bolt them to each of the ties. These serve as the base, from which spring the sides ot' the tube,

and, being connected with the ties, the whole constitutes a strong frame as a foundation for thestructure above. The outer side of eac of these timbersis grooved, as at ct, Fig. 1, to

receive the lower edge of a series of planks,

dd, which compose the arched or circular,

portion of the tube. These planks may be from two` to 'three inches or more in thickness, and from five to eight inches wide, more or less,:and are closely iitted together at their 'edges and ends by tongues and grooves, and joined with lead and oil or other suitable cement, to render them air-tight. rEhe end joints will alternate to insure the greatest strength, and Yat short intervals apart iron tend to open the joints.

bands c cinclose the planked portion. These bands are formed in two segments, each being bolted to the string-timbers G U, and their oppositeends, which are provided with vertical ears f f, approach near to eachother at the top of the tube, and are connected by a screw-bolt, g, by thetightening of which the planking can at any time be compressed to compensate for any shrinkage which might At a point a little above where the planks are jointed to the string-timbers C C, and preferably at or near the point of greatest horizontal diameter of `the tube, on either side, are placed inclined boards J, (or, ifpreferred, metal flan ges or gut ters may be used,) to carry od' the rain which falls on the tube, and prevent it entering the` joints at a a, and subjecting the timbers to decay. The space at the bottom ot', the tubeis then closed by planking between the ties,

the planks being laidqtransversely as showir at b, Fig. 2, and secured to the under sides ot' .the timbers C C, all the joints being calked or otherwise made tight, so that the entire tube may be hermetic. j 4 f lf found practicable, the bed o r under sur face of thek tube may be laid with Water-limeor other cement, level with or covering the surface of the ties, so as to exclude the air.

At intervals of iive or ten miles (more or. less, as experience may determine) hollow shafts ortowers D are erected, which cominunieate through openings with the interior` of the tube; and connected with these areV engines for exhausting a sufficient portion ot' the air contained within the tube to obtain,"

`bythe pressure of air admitted on the oppoh `site side of a car adapted to the purpose, sutiicient motive-power for the propulsion of a train atthe required speed. Sufficient strength of materials and their fastenings must behad to resist the external pressure of the atmosphere, which will equal, on all parts of the tube, that required to be exerted on the area of the transversesection to propel the train; At'stations intowns and cities the tube will -termiiiate within the depot building, and re`A commence at the opposite side thereof, theA The ends track being continuous as usual.

of the tube are to be provided with swingavailable by simple means to transfer trains portions of the segmental valves. The dimensions of these smaller valves is such that when opened the remaining area of the major part ofthe valves h is reduced to less than that of the inner part of said valves, so that the pressure of air becomes greatest ou the inner part from the opening of the valves z t', and the valves 7L h turn automatically in the direction of the motion of the car, ornearly so. The axes of the valves i z' are placed at right angles to those of the segmental valves in which they are hung, being vertical in -those of the latter, which are hinged to swing horizontally, and vice versa, by which arrangement both classes of valves (la and i) present only their edges to the current of air When both are open, and thus all pressure is removed. The valves z' t' have rods or chains connected with them in any suitable manner, whichv extend to the cab of the engineer, and enable him to open or close them at Will.

doors L L, Fig. 4, which open for the passage of the cars, but are closed when the train is approachingin order that a partial vacuum may be maintained within the tube. An airtight joint may be provided by a flat strip 'of rubber packing, l l, on the door casing or frame, and correspondingly arranged angular ribs or strips of Wood or metal, z', on the doors,

passengers and y small freight pass, these doors to be constructed with air-tight joints in the manner described or in some other suitable Way. At large stations suitable provision for the passage of meeting trains Would be provided by side tracks in the depot building, where the power of the stationary engines at a little incline When opened, so that the current of air from behind may act upon them, and when the engineer shuts the smaller valves increasing the area Will close them automatically. By openin g a lesser or greater number of these segmental valves the speed of the train may be regulated and varied as required. v

In crossing streams or gullies the tube vshould be constructed upon bridges, built iu the ordinary manner, and securely fastened thereto.

The inner edge of the large valves h 7L may be made to strike against pins or bolts, instead of against rabbets, the said pins or bolts 1 being inserted in a manner that they can be and move and transport cars, as required.

The propelling-car is construct-ed with a platform mounted upon ordinary wheels having a transverse frame, k, erected preferably near its center, back of which is an apartment the sidesvof this frame are hinged a series of valves, h h 7L h, of such size, and so arranged that when shut they form, in connection with the car body, a diaphragm which closes the aperture ofthe tube, or nearly so, like a piston, the extreme edges of those at the top and sides being' segmental to conform to the shape ofthe tube. rlhe axes of these hinged valves are eccentric in respect to area, allowing' the larger proportion of surface outside of the opposite side of the inner edge of these valves, thus permitting the draft-car to back the train at any point in the tube Without having to turn the car around, and also to avoid the neeessity of building so many turntables. This mode of construction is specially devised to obviate an objection which appertains to pneumatic-railway trainsfor couveyingpassengers, viz: that the smoke, gases, Ste., accumulate and are carried along with the train, having a deleterious effect on the passengers and exposi-ng them to sut'focation; but the provision herein described, viz: the space around the of travel, the outer portions turning backward when opened, as in Fig. 2. By this arrangement the pressure of the atmosphere the tube, so as to form, collectively, a diaphragm or piston, against Which the atmospheric pressure is exerted to propel the car. The diaphragm or piston, While conforming to the Walls of the tube, does not fit closely to the rear of the train, by which deleterious gases and foul air are carried back from' the f train and left in the rear.

which Would pass through the surrounding What I claim as my invention, is interstices without exerting pressure on the l. A pneumatic-railway tube formed of the piston. longitudinal stringers C C, with cross-ties A y In order to reduce the speed or stop the A, and planks b b bolted thereto, in combinatrain, the valves la zl1, la must be partially or tion with the circular arched shell composed Wholly opened, to diminish the pressure of of the pieces d d and bands c e, constructed the air. This is effected by means ofone ormore and arranged as and for the purposes set forth. auxiliary valves, it', hung in the larger outer 2. In combination With the track, the

stringers C G forming a continuous guard the entire length of the road, vto prevent the Wheels jumping the track, as set forth.

3. In combination with the segmental sections 7L h, the auxiliary valves z' i, arranged and operating substantially as and for the purpose shown and described.

4. In combination With the 'curved sides d d and longitudinal stringers C C, the inclined Waterguard J, as and for the purpose set forth.

5. 'Ihe angular ribs i" i in `combination with the fiat rubber strips Z l, for excluding air from the pneumatic tube when the doors' L L are closed, substantially as set forth.

6. A diaphragm for a pneumatic-railway car, portions ot which are formed of hinged sections h h, substantially as and for the purpose set forth. r

In Witness whereof', I have hereunto signed my naine in the presence of two subscribing Witnesses.

ROLLIN R. GREGG. Witnesses:

J. R. BRAKE, BENJ. H. AUSTIN; 

